Jon,
My buddy built one a few years ago, worked well when he was restoring his 63 Impala. It beat the heck out of crawling under the car to weld new floor pans. It is a lot of steel to store though.
Unless you are planning to restore a lot of vehicles, kind of a waste of money. I also have another friend that built one on an old boat trailer (smaller version). Works well for taking the body to the sand blaster.
-RT1
